What this -12 V regulator brings to the board
The ON Semiconductor MC79L12ACDR is a fixed -12 V negative linear regulator in an 8-SOIC surface-mount package, rated for 100 mA continuous output. The 42 dB PSRR at 120 Hz attenuates rectified mains ripple.
The 8-SOIC body (3.90 mm width, 0.154" pitch) is the standard narrow SOIC footprint. It's a direct drop-in for any 8-pin SOIC negative regulator layout — no adapter board, no lead bending.
Temperature grade — where it lives and where it doesn't
Rated 0°C to 125°C operating junction temperature. The 125°C upper limit is junction temp, not ambient — derate for self-heating at 100 mA.